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Distribution of aerosol particles from ship diesel engines
Šmok, Dominik ; Hovorka, Jan (advisor) ; Vojtíšek, Michal (referee)
3 Abstract Measurements of aerosol particle size distributions in the range 5 nm - 4 µm at 1.5 m above sea level were carried out on board a boat in German waters of the Baltic Sea. The measurements were aimed at characterizing aerosol particles from marine aerosol and from ship diesel engines and their dynamics, i.e. the aging of the exhaust plume in the marine boundary layer. The marine aerosol of PNC5-340 1335-1939 cm-3 is characterized by Aitken, accumulation and coarse modes of CMD 20 and 41-55 nm and 123-159 nm and 1.6 µm, respectively. The ratio of the accumulation to the Aitken mode increases with increasing shipping density. Aerosol particles from diesel engines in exhaust plumes with an age of 2 - 60 s and at a distance of 150 - 600 m from the surveyed ships are characterized by PNC5-340 1-4 -105 cm-3 and CMD 20 nm. The modal size distribution of supermicron particles of Da 1 - 4 µm does not change in the exhaust plume, the total mass of supermicron particles increases only by 1 - 6% compared to the background. The dynamics of the size distributions of aerosol particle numbers is mainly due to the formation, i.e. expansion and dilution, of the plume. However, in the exhaust plume with an age of 6 - 16 s and at a distance of 50 - 150 m, a faster decrease was observed for PNC20 due to the...
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PM2.5 field in the air of Družec village during heating season
Šmok, Dominik ; Hovorka, Jan (advisor) ; Kozáková, Jana (referee)
Residential heating by solid fuel combustion in small settlements has great potential to degrade air quality, especially PM2.5 emissions, during the winter heating season, to such an extent, that WHO and US-EPA limits for PM2.5 are frequently exceeded. There were found significant temporal variability and spatial heterogeneity of the PM2.5 concentration field. 24h limit for PM2.5 (US-EPA, 35 μg∙m-3) using a stationary network of 6 monitors measuring minute concentration of PM2.5, In the village Družec, Kladno district, during the 14-day measuring campaign. Campaign average exceeded the limit at the primary school garden. In the other sites, the limit was usually exceeded occasionally except one day, when the limit exceedance was recorded in all the sites as well at the whole area of the Czech Republic. The analysis of time course of minute values of PM2.5 shows that the residential heating increased PM2.5 concentrations on average by 61-72% (16-25 g∙m-3) or 40-49% (6-10 g∙m-3) at exposed or background sites respectively; PM2.5 values decreased exponentially with wind speed up to 2 m∙s-1, when they stabilized at 8-16 g∙m-3. At the microscale of the village, there were also found spatial and temporal heterogeneity of PM2.5 and aerosol particle concentrations PNC using by mobile measurement of PNC...
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